(1) Field of the Invention
The present invention relates to a mat having a good flame-proofness and a good dust-controlling property in combination. More particularly, the present invention relates to a dust-controlling mat comprising tufted pile yarns of fibers composed of a grafting product or polymer blend including polyvinyl alcohol and polyvinyl chloride.
(2) Description of the Prior Art
Dust-controlling mats are placed in the vicinity of entrances of stores, hospitals, offices and other buildings for the service trade and used for preventing dusts from intruding into these buildings from the outside. These dust-controlling mats are ordinarily prepared by tufting pile yarns to a base fabric, fixing the tufts by a packing of a synthetic rubber and coating or impregnating the tufted yarns with a dust-controlling composition containing an oiling agent. Fibers to be used for tufting should have a property of adsorbing and retaining an oiling agent therein. For this reason, flammable fibers such as cotton fibers and Vinylon fibers (polyvinyl alcohol fibers) have been mainly used. Furthermore, these flammable fibers are coated or impregnated with an oiling agent which also is flammable. Therefore, the conventional dust-controlling mats catch fire easily and are very poor in the flame-proofness.
Recently, regulations of the flame-proofness to matting articles have become stringent for fire prevention in urban communities, and the Fire Services Act and related laws stipulate that matting articles used at multistoried buildings, underground markets and buildings and halls where many and unspecified persons gather should have a certain flame-proofness.
Accordingly, various attempts have heretofore been made to improve the flame-proofness in dust-controlling mats. According to most of these conventional attempts, flame-proofing agents are incorporated into dust adsorbing oiling agent compositions. For example, the specification of U.S. Pat. No. 3,391,097 discloses a process in which a flame-proofing agent composed of an antimony-phosphorus pentoxide complex or the like is mixed with a mineral oil and an emulsifier to form a dust-collecting self-emulsifiable oiling agent composition and a cellulose fiber mat is treated with an aqueous emulsion of this oiling agent composition to form a dust-controlling mat, that is, a so-called walk-off mat.
Indeed, this flame-proofing mat is improved over mats prepared by using an oiling agent composition free of a flame-proofing agent with respect to the flame-proofness. However, since the constituent fibers are very easily flammable, the flame-proofness is still insufficient. Furthermore, this mat is defective in that the durability of the flame-proofness is poor.
It may be considered that the foregoing defects will be overcome by using flame-proofing or flame-retardant fibers as the constituent fibers. However, most of available flame-proofing or flame-retardant fibers lack the property of adsorbing and retaining dust absorbing agents such as the above-mentioned oiling agents, and when they are used for dust-controlling mats, a sufficient dust adsorbing property or dust retaining property cannot be obtained. Moreover, in dust-controlling mats prepared by using these flame-proofing or flame-retardant fibers, the dust adsorbing agent such as an oiling agent is readily transferred to boot soles and the like and the portion near the place where the mat is placed is readily contaminated.